__gettod.c

一个C源代码分析器

/* Copyright (C) 1991, 1992, 1994 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <ansidecl.h>
#include <errno.h>
#include <time.h>
#include <sys/time.h>

#ifndef HAVE_GNU_LD
#define __daylight	daylight
#define __timezone	timezone
#define __tzname	tzname
#endif


/* Get the current time of day and timezone information,
   putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
   Returns 0 on success, -1 on errors.  */
int
DEFUN(__gettimeofday, (tv, tz),
      struct timeval *tv AND struct timezone *tz)
{
  if (tv == NULL)
    {
      errno = EINVAL;
      return -1;
    }

  tv->tv_sec = (long int) time ((time_t *) NULL);
  tv->tv_usec = 0L;

  if (tz != NULL)
    {
      CONST time_t timer = tv->tv_sec;
      CONST struct tm *tm;

      CONST long int save_timezone = __timezone;
      CONST long int save_daylight = __daylight;
      char *save_tzname[2];
      save_tzname[0] = __tzname[0];
      save_tzname[1] = __tzname[1];

      tm = localtime (&timer);

      tz->tz_minuteswest = __timezone / 60;
      tz->tz_dsttime = __daylight;

      __timezone = save_timezone;
      __daylight = save_daylight;
      __tzname[0] = save_tzname[0];
      __tzname[1] = save_tzname[1];

      if (tm == NULL)
	return -1;
    }

  return 0;
}